In Junior high, circa 1970, the lunch ladies made chocolate sheet cakes with thick chocolate icing. They sold them from a separate stand in the dining room, along with extra milks. A 4" square of cake was 12 cents, and milk 3 cents.
I'm not a person with a heavy sweet tooth. The icing was way too sweet for my tastes. But the cake without icing was delicious to me.
I discovered that many of my classmates had already entered the full blown phase of their sugar addiction. I would buy a piece of cake and a milk, sit down, turn the cake icing-side-down on the saucer, and pull the cake free of the icing. I'd finish the moist cake, finish my milk, then show the icing to a sugarhead and offer to let them have that sweet thick elixir if only they would go to the cake stand, buy a square, bring it back and give me the cake, so then they'd have two glistening saucerfulls of icing. Sensing the market could bear more, I'd add "Oh, and you'll need to buy me a milk, too."
So, for fifteen cents, I scored thirty cents worth of cake (minus icing) and two milks. All the mark got was cavities and two slabs of icing, at an outlay of 26 cents for two cakes.
Through those cafeteria years, I found that if I focused on sweets as the legal tender, then any item of the meal, even the entree, was easily gotten. Sometimes a trade required a few additional Hershey's Kisses or Pixie Sticks that I carried in my book bag as wampum.
Sometimes the day's item was so unpopular that I'd get them for free, just for doing them the favor of getting it off their plate so they wouldn't have to look at it. Turkey fricassee was an easy gimme, as were pinto beans from those that feared the later classroom flatulence. On days of canned spinach or kale I'd ask the lunch ladies for an extra bowl, because those greens were a sure sweep.
Then came the last two years of high school, where I brown-bagged it. We sackers ate in the lounge, not the full cafeteria. This was a tougher market, since everyone had a chance to have input each morning about the contents of their lunch bag. Those folks who made their own sandwiches usually kept their stuff, but those who were coddled at that age to have a parent make it gave up the goods a lot easier.
By now, given the advanced savvy of these older adolescents, I'd had to shift my barter goods away from Pixie Sticks and move up to Halloween size candy bars. But addiction is a horrible thing, and the sugar fix meant that I could easily trade a bar for a savory sandwich. Snickers seemed to have the most appeal, and it assuaged my guilt a bit as I knew the peanuts would give them at least a little protein for the afternoon as I freed them of that beautiful ham or tuna sandwich. With bag lunches it was easy to develop some regular customers, some of whom started asking Mom for two sandwiches in the sack, not telling her that one would be converted to Snickers.
So what were your experiences with swaps? Were there certain items that traded easier? What were the outright freebies?